JPH01256120A - Heat-treating method for semiconductor substrate and its equipment - Google Patents

Abstract

PURPOSE:To obtain an uniformly growing film or an impurity diffusion layer on a substrate surface, by heat-treating the semiconductor substrate inserted in a heat-treating furnace, while rotating it by setting the center of the semiconductor substrate as the rotary shaft center. CONSTITUTION:A boat 4 mounting substrates 2 is so loaded that four rotary rollers 13 fixed on a sled 3a and a fixing ring 7 of the boat 4 engage each other. The sled 3a loaded with a boat 4 is slowly pushed by rotating a quartz rod 6 with a rotation driving equipment fixed on the rear end of a quartz rod 6. Thus the sled 3a is inserted in a furnace core tube 1 heated previously by a heater 11. The furnace core tube 1 is closed with a cap 8, and reaction gas 9 is introduced. After heating is continued for a specified time, the heat treatment is finished. Thereby, the temperature gradient in the substrate surface is reduced, and further the distribution of reaction gas is uniformized, so that an uniformly growing film and an impurity diffusion layer are obtained in the semiconductor surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for heat treating a semiconductor substrate.

[Conventional technology]

Conventionally, heat treatment steps for semiconductor substrates include forming a thermal oxide film, introducing and diffusing impurities, and annealing after ion implantation.

In particular, uniform film thickness has become required for the formation of oxide films and the introduction and diffusion of impurities.

FIG. 5 is a sectional view of a horizontal heat treatment furnace for explaining conventional heat treatment. First, several dozen semiconductor substrates (hereinafter referred to as substrates) are inserted into the grooves (not shown) of the quartz boat 1-'4c and loaded vertically.Next, the boat 4C loaded with the substrates 2 is loaded. Put it on sled 3C.

Next, the sled 3c is moved by the rod 6 driven by the boat loader 5.
Press to insert it into the furnace core tube 1 which has been heated by the heater 11 in advance. Next, the furnace core tube 1 is closed with a cap 8, and the reaction gas 9 is supplied from the gas supply port at the other end of the furnace core tube 1.
will be introduced. Next, the substrate is heated for a predetermined period of time to form a produced film or an impurity diffusion layer.

[Problem to be solved by the invention]

In the conventional method and apparatus described above, a temperature gradient is created between the upper and lower parts of the furnace core tube, resulting in temperature unevenness within the substrate surface, resulting in non-uniform thickness of the produced film or impurity diffusion layer. Furthermore, due to this temperature gradient, the reaction gas also causes thermal convection, which promotes non-uniformity. Various attempts have been made to solve this problem, such as adjusting the height of the substrate, improving the shape of the furnace cap, and minimizing the flow of reactant gas to reduce the thermal gradient. We have not yet reached a fundamental solution.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for heat-treating a semiconductor substrate, by which a uniformly formed film or impurity diffusion layer can be obtained within the plane of the substrate.

[Means to solve the problem]

The heat treatment method for a semiconductor substrate of the present invention is a method of heat treating a semiconductor substrate at high temperature by thermal oxidation, thermal acid expansion, etc., in which the semiconductor substrate inserted into a heat treatment furnace is rotated about the center of the semiconductor substrate as a rotation axis. The system includes a method and mechanism for heat treatment. Furthermore, the heat treatment apparatus of the present invention includes:
A heat treatment apparatus that heat-treats semiconductor substrates by thermal oxidation, thermal acid expansion, etc. at high temperatures has a substrate loading mechanism located inside a furnace core tube for loading the semiconductor substrates, and a substrate loading mechanism located outside the furnace core tube for loading the semiconductor substrates. and a rotational drive source that rotates the loaded semiconductor substrates around the center of the rotation axis.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a cross-sectional view of a horizontal heat treatment apparatus showing a first embodiment of the present invention, and FIGS. 2 and 3 are a rotation transmitter F? in FIG. 1.
410 is an enlarged cross-sectional view and front view. First, the lower boat 4a of quartz boat)-4, which is made of two parts.
The substrates 2 are inserted into grooves (not shown) in the four support rods 12, and several dozen substrates 2 are placed vertically in line. Next, an upper boat 4b manufactured symmetrically with the lower boat 4a is placed on top of the lower boat 4a, and the two fixing rings 7 are fitted and fixed into the cylindrical portions at both ends of the boat 4 consisting of the upper boat 4b and the lower boat 4a. Next, the boat 4 loaded with the substrates 2 is placed on the boat 4 so that the four rotating rollers 13 attached to the sled 3a and the fixing rings of the boat 4 are respectively fitted. Next, the rod 6 is rotated and slowly pushed by a rotary drive device (not shown) attached to the rear end of the quartz rod 6, and the sled 3a carrying the boat 4 is heated in advance by the heater 11. It is inserted into the furnace core tube, the furnace core tube 1 is closed with the cap 8, and the reaction gas 9 is introduced. Next, heat treatment is completed by heating for a predetermined time. As a result, for example, in the case of forming a thermal oxide film, the variation in the thickness of the oxide film within the substrate surface was only about ±4% with the conventional method, but with this method The variation in film thickness could be kept within ±1.5%.

FIG. 4 is a sectional view of a horizontal heat treatment furnace showing a second embodiment of the present invention. This device is an example in which a conventional plane paddle is used instead of the boat loader 5 for transporting the boat. The same bows 1 to 4 as used in the first embodiment are inserted through the tip opening of the cannabattle 14, and the cannabattle 14 is rotated by a rotational drive device (not shown) connected to the other end of the cannabattle 14. Other than this, the second embodiment is the same as the first embodiment. Compared to the first embodiment, this device has the advantage that dust is less likely to be generated because there is no rotation transmission mechanism in the furnace core tube.

〔Effect of the invention〕

As explained above, the heat treatment method and apparatus according to the present invention reduces the temperature gradient within the substrate plane by rotating the substrate, and also makes the distribution of the reaction gas uniform, so that uniform formed films and impurities are generated within the substrate plane. This has the effect of providing a diffusion layer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a horizontal heat treatment apparatus showing a first embodiment of the present invention, and FIGS. 2 and 3 are a rotation transmission mechanism 1 in FIG. 1.
0 is an enlarged cross-sectional view and front view, and FIG.
FIG. 5 is a sectional view of a horizontal heat treatment furnace for explaining conventional heat treatment. 1...Furnace core tube, 2...Semiconductor substrate, 3a, 3C...
Sled, 4... Boat, 4a... Lower boat, 4b.
... Upper boat, 5... Boat loader, 6... Bar,
7... Fixed ring, 8... Cap, 9... Reactive gas, 10... Rotation transmission mechanism, 11... Heater, 1
2... Support rod, 13... Rotating roller, 14... Cantilever paddle.

Claims (1)

[Claims] 1. In a method of heat-treating a semiconductor substrate at high temperature, such as thermal oxidation or thermal expansion, the semiconductor substrate inserted into a heat treatment furnace is rotated about the center of the semiconductor substrate as a rotation axis. A method for heat treatment of a semiconductor substrate, characterized by subjecting it to heat treatment. 2. A heat treatment apparatus for heat-treating semiconductor substrates by thermal oxidation, thermal expansion, etc. at high temperatures, including a substrate loading mechanism located inside the furnace core tube for loading the semiconductor substrates, and a substrate loading mechanism located outside the furnace core tube for loading the semiconductor substrates. 1. A heat treatment apparatus for semiconductor substrates, comprising: a rotational drive source for rotating a mechanism about the center of the loaded semiconductor substrates as a rotation axis.